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Co-authored-by: Martin Šošić <Martinsos@users.noreply.github.com>

waspc/src/Analyzer/TypeChecker.hs

@@ -1,4 +1,4 @@
--- | This module exports the functions necessary typecheck AST from "Analyzer.Parser".
+-- | This module exports the functions necessary for typechecking the AST from "Analyzer.Parser".
 -- See the Type Checking section in "docs/wasplang" for the rules type checking follows.
 --
 -- See "Analyzer.TypeChecker.Internal" for the implementation of the type checking rules.
@@ -27,7 +27,7 @@ import Analyzer.TypeChecker.Monad (runT)
 import Analyzer.TypeChecker.TypeError
 import Analyzer.TypeDefinitions (TypeDefinitions)
 
--- | Checks that an AST conforms to the type rules of Wasp and produces a
+-- | Checks that an AST conforms to the type rules of Wasp and produces
 --   an AST labelled with type information.
 typeCheck :: TypeDefinitions -> AST -> Either TypeError TypedAST
 typeCheck typeDefs ast = runT typeDefs $ check ast

waspc/src/Analyzer/TypeChecker/Internal.hs

@@ -185,10 +185,10 @@ weaken typ' expr
 -- A list can be weakened to @typ@ if
 -- - @typ@ is of the form @ListType typ'@
 -- - Every value in the list can be weakened to @typ'@
-weaken (ListType typ') expr@(List vals _) =
-  fmap (\values -> List values (ListType typ')) $
-    left (\e -> WeakenError (ReasonList e) expr typ') $
-      mapM (weaken typ') vals
+weaken type'@(ListType elemType') expr@(List elems _) = do
+  elems' <- left (\e -> WeakenError (ReasonList e) expr elemType') $
+    mapM (weaken elemType') elems
+  return $ List elems' type'
 weaken (DictType typ') expr@(Dict entries _) = do
   entries' <- mapM weakenEntry entries
   mapM_ guardHasEntry $ M.toList typ'

waspc/src/Analyzer/TypeChecker/TypeError.hs

@@ -26,7 +26,7 @@ data TypeCoerceReason
     ReasonEnum
   | -- | There is no relationship between the types in the coercion
     ReasonUncoercable
-  | -- | A coercion of the type contained in a list fialed
+  | -- | A coercion of the type contained in a list failed
     ReasonList TypeError
   | -- | A coercion failed because a dictionary was missing a key
     ReasonDictNoKey String

waspc/test/Analyzer/TypeCheckerTest.hs

@@ -8,8 +8,8 @@ import Data.Either (isRight)
 import qualified Data.HashMap.Strict as H
 import Test.Tasty.Hspec
 
-spec_Parser :: Spec
-spec_Parser = do
+spec_TypeChecker :: Spec
+spec_TypeChecker = do
   describe "Analyzer.TypeChecker" $ do
     describe "typeCheck" $ do
       it "Type checks a simple, well-typed example" $ do